Further studies are planned in the following areas relative to the pathogenesis of fever: (1) Further delineation of the sources and conditions of release of the nonpyrogenic lymphokine that mediates fevers of delayed hypersensitivity. (2) Further studies on the role of various tissues and cells in the pathogenesis of clinical fevers - especially those due to tumors and malignant lymphomas. (3) Delineation of various steps in the release and fate of endogenous pyrogen and the effect of various inflammatory and anti-inflammatory agents.